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                            // 一行打印五个星星 
                            // console.log('★★★★★');
                            // for (var i = 1; i <= 5; i++) {
                            //     console.log('★');
                            
                            // }
                            // var str = '';
                            // for (var i = 1; i <= 5; i++) {
                            //     str = str + '★';
                            // }
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        var num = prompt('请输入星星的个数');
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            str = str + '★'
        }
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